Milling is the process of machining using rotary tooling to remove material by advancing the tooling into the workpiece. This can be done by moving directions on one or several axes, tooling speed, and pressure. During a milling process, the workpiece remains stationary will the tooling moves into the piece. And while the concepts of CNC milling remain the same, there are different type of machines that execute this concept in different ways. In this blog post we will examine the differences between horizontal and vertical machining as well as the benefits and drawbacks of each type.
In today’s world, you will most likely find some version of a vertical milling machine in almost any machine shop. Vertical milling machines utilizes a vertically orientated spindle that holds and spins the tooling against the workpiece. On some machines, the quill will move the spindle along the vertical axis, also known as the Z axis. Additionally, depending on the machine, the worktable can move side to side (X axis), in and out (Y axis), and up and down (Z axis). Vertical milling machines are ideal for single sided machining operations.
Vertical mills can be divided into two machine types: bed mills and knee mills. Each have their own distinct characteristics and advantages. Most knee mills have a fixed spindle, and the worktable moves along the X, Y, and Z axes. In some cases, knee mills may have a quill to move the spindle along the Z. Knee mills vary in size all the way from standalone to small bench top models.
Unlike knee mills, bed mills feature a worktable that is either stationary or moves only along the X and Y axes. Bed mills are ideal for larger/heavier workpieces.
Uses for Vertical Machining
Due to their versatility, vertical milling machines are used throughout a wide variety of industries. Here is a snapshot of some of their uses:
- Prototyping or engraving
- Single Sided Projects
- Projects that require a lot of visability
- Plunging & Drilling
Advantages of Vertical Machining
Due to their widespread use and innovation many advantages can be drawn from the use of a vertical mill. Here are some of their advantages:
- Smaller investment compared to horizontal machines.
- Variety of footprint, styles, and configurations.
- Higher visibility of tooling.
- Easier maintenance and part availability.
- Less fixturing compared to their horizontal counterparts.
- Typically, easier to operate and learn.
Disadvantages to Vertical Machining
With all their versatility, there are some drawbacks to vertical machining. Here are some of the drawbacks:
- Many vertical milling machines utilize moveable air nozzles or through spindle air to clear chips when making cuts since gravity doesn’t aid chip evacuation like it does for their horizontal counterparts.
- Single side operation
- Slower production output compared to horizontal machining.
- Less tooling capacity
Horizontal milling machines are different than their vertical counterparts. The main key difference being the horizontally mounted spindle. Many horizontal machining centers today feature a two-pallet system which allows one pallet to be in operation while the operator can set up another workpiece on the other. This ability greatly increases productivity and throughput. Horizontal machining centers can also be integrated into automated pallet systems to keep fixtures and tooling at the ready for large volume production projects.
Uses for Horizontal Machining
Horizontal milling machines are often found in fabrication shops that can utilize their capacity and production output. Here are some the general uses for horizontal machining:
- Grooves, slots, drilling, and tapping on horizontal plane.
- Multi side operations
- Large and heavy workpieces or fabrications
- Large volume production
Advantages of Horizontal Machining
Due to their robust and semi-autonomous nature and their ability for multi sided operation, horizontal machines pose some advantages over their vertical counterparts. Here are some of the advantages of horizontal machining:
- Increased output
- More apt to be integrated with automation
- Multiple pallets for staging and machining work pieces (more spindle utilization).
- Equipped to handle very large workpieces and fabrications (i.e., boring bars)
- Gravity assisted chip evacuation which increases tool life and surface finish.
- Less deflection and vibration than vertical machining centers.
- More tooling capacity
Disadvantages to Horizontal Machining
Even with their advantages, horizontal machining centers may not be the best fit for every situation. Here are some of the disadvantages of horizontal machining:
- More expensive than vertical machining centers
- Typically, larger than vertical machining centers.
- Steeper learning curve for program and setup (i.e., more programming offsets, 4th axis, etc.)
- In some cases, more fixturing is required than a vertical machining center.
When it comes to deciding between horizontal and vertical machining, there is no clear-cut answer. However, analyzing your project’s needs can help identify which type of machining is right for the project. In most use cases, vertical machining is more apt for lower volume work that is prone to a lot of job changes. Horizontal machining can be better suited for high volume production work to keep efficiencies high and costs competitive. However, they can be easily utilized for low volume production as well.
About Innovative Machining
Innovative Machining LLC is a full service CNC machine and fabrication facility with over 125,000 square feet of manufacturing space. We carry a full line up of vertical and horizontal CNC machining centers to bring your next project to life. Check out what we can do for you today!